Overheated buss

[TwinCitySparky]

I see what you are talking about now A bus detail seems to be behind the threaded plate of the breaker connection thereby the bolt socked up tight into the breaker contact and the buss detail was just sitting loosely behind it with the bolt running through the unthreaded hole of the bus detail. NICE!!!!

I just ran into almost the same scenario at an apt. building recently. Goofy voltages in one unit pointed to a neutral problem. I found what appeared to be a loose neutral bar connection in the switchgear. You could tell by the damaged screw head that someone tryed repeatedly to crank it down. After staring at it for 5 minutes, on my second trip back with building owner next to me... I finally realized this small screw was threaded in from the front of the switchgear, instead of the back like the rest of the screws holding the equipment together. (factory mistake from 50 years before!) This created the same situation where the screw was threaded tight into the first peice of metal it passed thru, then just passed thru the unthreaded busbar below it... Everything sure appeared to be tight. I wonder how many appliances were toasted over the years.

 

[charlie tuna]

this breaker failed one time(?) -- there was a reason it failed(?) -- the bus finger might have been the original problem that caused the breaker to fail??? being in the infrared field for many years i have seen problems like this many times. without looking at this installation under load with an infrared camera you are just guessing. yes the bolt can be tight---but is the bolt head fully engaged into the bus bar?? and when equipment gets hot enough to discolor the metal fingers they need to be changed --their current carrying capabilities have changed. never use a reconditioned or used breaker unless it's an emergency, many times the reconditioned one is in worst condition than the original one!

alot of our electrical equipment operates just fine --- but take that load up to 80 per cent continuous -- with a load like an elevator or heavy motor load and that equipment begins to break down!! when a breaker like this size fails slapping another used breaker in it's place is really only a temporary measure! you need to monitor the load and voltage to determine if the system is designed properly--who knows--some load might have changed over the years?? you may have a voltage drop problem upstream of this breaker. we can all guess at whats happening --- you need to investigate with infrared to actually determine where the problem is!!

 

[zog]

"never use a reconditioned or used breaker unless it's an emergency, many times the reconditioned one is in worst condition than the original one"

Thats a pretty bold statement there Charlie, a properly reconditioned breaker (per PEARL standards for example) can be better than it was when it was new, newer better materials used to replace older wearable parts and newer electronic trip systems to replace older magnetic devices.

Older breakers were "overbuilt" and have withstanded the tests of time, when properly maintained and properly reconditioned they are better than the new cheaply made stuff on the market today.

Granted there is alot of junk out there called reconditioned because someone cleaned it up but you get what you pay for. It should come with test records and a warantee. I am guessing from your statement that you have previous experince buying the cheapest "reconditioned" stuff you could find and have had problems, ever wonder why it was so cheap?

 

[weressl]

"never use a reconditioned or used breaker unless it's an emergency, many times the reconditioned one is in worst condition than the original one"

Thats a pretty bold statement there Charlie, a properly reconditioned breaker (per PEARL standards for example) can be better than it was when it was new, newer better materials used to replace older wearable parts and newer electronic trip systems to replace older magnetic devices.

Older breakers were "overbuilt" and have withstanded the tests of time, when properly maintained and properly reconditioned they are better than the new cheaply made stuff on the market today.

Granted there is alot of junk out there called reconditioned because someone cleaned it up but you get what you pay for. It should come with test records and a warantee. I am guessing from your statement that you have previous experince buying the cheapest "reconditioned" stuff you could find and have had problems, ever wonder why it was so cheap?

I think at this point clarifications are in order.

MCB or open frame, withdrawable are two different animals.

MCB's are usually sealed breakers and unless the shop has UL certification - which nonexisten for MCB's - as soon you break the seal the certification is gone.

If a system breaker is rebuilt, reconditioned in a certified shop then the breaker with upgraded OC protection can perform according to the original certification.

Lastly there are more "shops" out there that are doing shady business than legitimate, certified repair shops with reputable records, so if you buy a used or reconditioned breaker, shake the trees and move the earth before commiting those to service. People's life could depend on your decision and that still worth more than the savings.

 

[zog]

Agreed on all points made Laszlo

 

[templdl]

It is common for MCCBs with 250a frames and above to be available as "sealed" noninterchangeable trip (NIT)and "unsealed" interchangeable trip (IT) breakers.

Yes, breaking the seal of a NIT breaker will void UL.

However, IT breaker you will not void UL unless there is an attempt to modify or repair the breaker. You can take the cover off because you are allowed to replace the trip unit and to add UL listed accessories in the field. I would like to see more technicians and electricians remove the covers of breakers where there are allowed to do so. If a breaker has interrupted some pretty significant faults the arc chute area will look like world war three. Most breakers may look almost brand new if they have never been opened or closed or simply opened and closed under normal load.

But refurbishing the breaker is another issue. How does one define refurbishing?
If there is no issue with taking the cover off there is no issue with taking it off to inspect the moving and stationary contacts. Most breakers that I've have had apart you can remove the arc chutes for a better view of the contacts. They slip right back in place. There is nothing in the instruction manual that I'm familiar with, that is Westinghouse and C-H, which prevents you from doing so. A breaker can look bright and shiny on the outside but you can't tell what the inside is like until you take the cover off.

If one attempts to refurbish the inside of the breaker cleaning can remove the lubrication that is required for the moving parts. Unless you are factory trained and authorized to do so the breaker may not function properly. And contact spring tension, latching mechanism, etc, etc. 40+ years ago Westinghouse do offer renewal parts for MCCBs which I found to be very interesting to say the lease. But things were a bit looser back then and liability was not as big an issue as it is today. I may have some old renewal parts sheets to prove it if I haven?t thrown them away.

And how about those breakers that have been submersed in food water? How many of those have been cleaned up and sold at a "good price" on the open market.
I sad to know that there are those who believe that as long as the hole in the panel is filled and the breaker is not required protect by tripping nobody will ever know the difference. One could conceivably put a dummy breaker in and as long as there are not overloads or short circuits nobody would ever know.

I would be very hesitant to purchase sealed breakers on the used market because I couldn?t tell what the breaker is actually like on the inside.
With and IT breaker that is not sealed I can simply remove the cover and inspect it. If it is clean while not looking as though it had been cleaned (refurbished), the contacts and arc chutes are in reasonable good shape and there is no sign of tampering or heating I would be inclined to accept it. With a used breaker I would feel much more comfortable if it were also tested according to NEMA AB4 a test procedure that I understand NETA uses.

 

[ptonsparky]

...and on that last note, here is the replacement provided to me:

 

[zog]

"But refurbishing the breaker is another issue. How does one define refurbishing?"

Should be refurbished per PEARL stabdards, heres a link to the standards

http://www.pearl1.org/download_PEARL_reconditioning_standards.htm

 

[templdl]

Tom,
That breaker looks superb.
When considering a breaker that looks in such pristine condition how did it get that way?
Other than being brand new from the factory how was it refurbished?
The manufacturer must go through all sorts of UL tests and maintain quality throughout the manufacturing process to maintain the UL label that includes calibration with extremely expensive equipment. They also must back a warranty and must consider their liability.

Which a referbisher can they parallel those of which the manufacturer must follow and what is their exposure when it comes to liability.

I would like to think that when one purchased an impeccably looking breaker as you have picture that one would expect the same security and confidence as those purchase brand new from the manufacturer. If not, what is it that's being compromised?
Other than cleaning the inside of the breaker if the contacts have been resurfaced or the lubricants have been removed or removed and replaced does the breaker continue to meat the original manufacturer?s specifications?

It is not my intent at all to discourage refurbished breakers just as long as one can be assured that the quality has not been compromised. And who determines that? I have always hung my hat on NEMA AB4 as an established method of field testing breakers. I sort of a set of rules where everybody who uses it to test breakers plays by the same rules. When one deviates from them then it becomes opinion unless that deviation is based upon or follows those specifications that the manufacture must follow.

This is a subject that generates many debates. As a professional one would like to think that, when our client pays for a service and we suggest that a refurbished product be installed, we have not simply filled a space in a panel with a shiny refurbished breaker. But that it will operate and protect when required doing so. I would also like to assume that a good majority of breakers are never required to trip due to an overload of fault so a defective breaker may never be discovered if it were simply capable of turning on and off manually.

Dave

 

[zog]

Again Dave you asked a question about a standard, I provided the standard and you didnt even give it a look and go on to ask the same question again.

There are some junk dealers out there, and ones that just make a breaker look pretty with out testing and/or quality controls in place, but the good ones follow established standards. Lubricants should be removed and replaced with the OEM recommended lubricants, wearable parts are not just cleaned up, they are replaced with new parts, etc.

 

[ptonsparky]

The circuit breaker does look good. Phase A has some contact wear that has been smoothed out, but B & C show none. Good, bad? I don't know. I will see how it looks after running for a week.

We get to start cleaning up connections, replacing conductors etc once this production run is complete. The starter is "end of life" and I will have to see what management decides. A "soft start" might be an option if the AHJ will accept the modification.